MULTIPLE DOCUMENT INTERFACE (MDI) WINDOWS 

The SDI (Single document interface) supports one open window or document at a particular time. Microsoft's notepad and paint are illustrations of the single document interface. As we know that the SDI applications have restricted capabilities. They have limited text and image - editing features. The Multiple document interfaces allow the users to edit multiple documents at similar time as shown in figure. The Adobe Photoshop allows editing the multiple images at similar time.

Figure: MDI Window

The most important window in a MDI program is the parent window. The all other windows of the application are child windows. The MDI program will have only one parent window and numerous child windows. Merely one child window will be open at one time. The uses of the child windows can differ. A child window could be used for editing the images; the second child window could be used for editing the text. Minimizing or Closing the parent window automatically closes the child windows.